[sdiy] OTA performance (was SSM chip reissue)

[Tom Wiltshire]

On 24 Apr 2017, at 22:38, Neil Johnson <neil.johnson71 at gmail.com> wrote:

>  0.24dB at Av = -40dB (after which they're too
> embarrassed to tell you how bad it is).

What, too embarrassed to say that the matching is a bit worse than a quarter decibel out at -40dB?!
What's the smallest decibel difference people can detect? About 3dB, isn't it? Quite a bit more than 0.25dB.

To be honest, if it were 1dB out by -60dB, who's really going to notice? 2dB out at -80dB? And that's a lot worse than the spec'd figures suggest is likely.

I guess it all hinges on how typical "typical" figures are, and what a standard deviation looks like on those numbers. 

Tom